The tracking issue for this feature is: None.
This feature is required to link to the
compiler_builtins crate which contains
"compiler intrinsics". Compiler intrinsics are software implementations of basic
operations like multiplication of
u64s. These intrinsics are only required on
platforms where these operations don't directly map to a hardware instruction.
You should never need to explicitly link to the
compiler_builtins crate when
building "std" programs as
compiler_builtins is already in the dependency
std. But you may need it when building
no_std binary crates. If
you get a linker error like:
$PWD/src/main.rs:11: undefined reference to `__aeabi_lmul' $PWD/src/main.rs:11: undefined reference to `__aeabi_uldivmod'
That means that you need to link to this crate.
When you link to this crate, make sure it only appears once in your crate
dependency graph. Also, it doesn't matter where in the dependency graph you
#![feature(compiler_builtins_lib)] #![no_std] extern crate compiler_builtins;